Many aircrafts mount two anti-collision lights, one light placed on the upper part of the fuselage and the other disposed on the bottom part of the fuselage to illuminate with the first one the upper hemisphere and with the second one the bottom hemisphere.
Usually, the upper anti-collision light covers the angle from 0° to +75° (with respect to an horizontal plane) whereas the bottom anti-collision light covers the angle from 0° to −75° (the field of coverage of the anti-collision lights is stated in FAR25-CS25/FAR23-CS23 par. 1401b).
Moreover, the anti-collision light is configured to flash in use (flashing characteristics of an aircraft anti-collision light are stated in FAR25-CS25/FAR23-CS23 par. 1401c).
LED light sources are particularly suitable for anti-collision aircraft lights since they allow for minimization of power consumption, have low failure rates and low cost, present a small volume and a reduced weight.
US2006007012 describes rotationally symmetrical anti-collision light for an aircraft utilizing light-emitting diodes (LEDs) configured in one or more concentric rings.
The anti-collision light includes reflector configured to redirect the light emitted by at least one of the rings, so that the light pattern satisfies predetermined specifications.
US2006077071 describes an anti collision light for aircraft including a number of light emitting diodes (LEDs) arranged on a common plane. A reflecting arrangement is located above the plane and reflects the light emitted by the diodes in a sideward direction. A surrounding reflecting arrangement can be provided around the diodes and an additional reflecting arrangement in form of a layer on the plane may also be utilized.
US2004130900 describes an anti-collision light for aircraft provided with a holding body with an outer side and several LEDs arranged at the outer side of the holding body the light-radiating directions of which point away from the holding body. The anti-collision light is provided with a refractive optical element for generating a desired spatial distribution of the light of the LEDs; the refractive optical element surrounding the holding body at least in the region of the LEDs.